Solar trough frame, part and method

ABSTRACT

A solar trough frame for holding solar mirrors includes a plurality of chords. The frame includes a plurality of extruded profiles, including chords, chord sleeves, struts, strut end pieces and mirror support pieces, each chord sleeve having at least one chord sleeve fin, each chord sleeve positioned about one of the chords. The frame includes a plurality of struts, at least one of the struts having a strut end piece having at least one strut fin that connects with a chord sleeve fin to connect the plurality of chords. The frame includes a platform supported by the chords and struts on which the solar mirrors are disposed. A chord sleeve for connecting a chord of a solar frame which supports solar mirrors to a strut end piece extending from a strut of the solar frame. A strut end piece for connecting the strut of a solar frame which supports solar mirrors to a chord sleeve of the solar frame. A method for linking a strut of a solar frame which supports solar mirrors to a chord of the solar frame. A method for supporting solar mirrors.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 12/583,787filed Aug. 26, 2009, now U.S. Pat. No. 8,887,470, which claims thebenefit of U.S. provisional application No. 61/190,573 filed Aug. 29,2008, all of which are incorporated by reference herein.

FIELD OF THE INVENTION

The present invention pertains to solar frames for holding solarmirrors. (As used herein, references to the “present invention” or“invention” relate to exemplary embodiments and not necessarily to everyembodiment encompassed by the appended claims.). More specifically, thepresent invention pertains to solar frames for holding solar mirrorsutilizing a plurality of extruded profiles, including chords, chordssleeves and strut end pieces, where each chord sleeve has at least onechord sleeve fin, and a plurality of struts, where at least one of thestruts has a strut end piece having at least one strut end piece finthat connects with a chord sleeve fin.

BACKGROUND OF THE INVENTION

This section is intended to introduce the reader to various aspects ofthe art that may be related to various aspects of the present invention.The following discussion is intended to provide information tofacilitate a better understanding of the present invention. Accordingly,it should be understood that statements in the following discussion areto be read in this light, and not as admissions of prior art.

Concentrating Solar Power (CSP) systems utilize mirrors to concentratethe sun's energy onto points or lines. For the purpose of explanation,we will assume a parabolic trough type system where the parabolicmirrors concentrate the sun's energy onto a fluid filled tube; the hotfluid is then transferred to a more conventional steam turbine powerplant or similar system to generate electricity. Reliable support forthe large parabolic mirrors is critical to ensure excellent performance(focus) in varying atmospheric conditions and to guard against mirrorbreakage. Some of the key issues include overall frame deflection fromits own weight, that of the attached mirrors and wind loads. Prior artfor Solar Trough designs relied on steel fabrications and weldments oraluminum extrusions configured and joined using techniques developed inthe building construction industry. We used our experience in buildingsafety critical structures from aluminum extrusions (ladders, stagingand scaffolding) and our extensive extrusion industry tooling andoperational knowledge and coupled this with the load and performancerequirements for solar trough frames; we used structural engineering andFinite Element Analyses (FEA) to design a more optimal solar troughframe—minimum weight, efficient production processes (extrusion,fabrication, subassembly and final assembly) with the end productdesigned to meet all weight, wind, temperature and torsional loadsexpected.

BRIEF SUMMARY OF THE INVENTION

The present invention pertains to a solar trough frame for holding solarmirrors. The frame comprises a plurality of chords. The frame comprisesa plurality of extruded profiles, including chords, chord sleeves,struts and strut end pieces, each chord sleeve having at least one chordsleeve fin, each chord sleeve positioned about one of the chords. Theframe comprises a plurality of struts, at least one of the struts havinga strut end piece having at least one strut end piece fin that connectswith a chord sleeve fin to connect the plurality of chords. The framecomprises a platform supported by the chords and struts on which thesolar mirrors are disposed.

The present invention pertains to a chord sleeve for connecting a chordof a solar frame which supports solar mirrors to a strut end pieceextending from a strut of the solar frame. The chord sleeve comprises achord sleeve primary portion having an opening in which the chord isdisposed; and at least one chord sleeve fin extending from the primaryportion that is fixed to the strut end piece.

The present invention pertains to a strut end piece for connecting thestrut of a solar frame which supports solar mirrors to a chord sleeve ofthe solar frame. The strut end piece comprises a strut end piece primaryportion which attaches to the strut. The strut end piece comprises atleast one strut end piece fin extending from the strut end piece primaryportion which attaches to the chord sleeve.

The present invention pertains to a method for linking a strut of asolar frame which supports solar mirrors to a chord of the solar frame.The method comprises the steps of positioning a strut end piece fin of astrut end piece of the strut adjacent a chord sleeve fin of a chordsleeve about the chord. There is the step of fixing the strut end piecefin and the chord sleeve fin together with a frame fastener thatcontacts the strut end piece fin and the chord sleeve fin.

The present invention pertains to a method for supporting solar mirrors.The method comprises the steps of receiving sunlight on the mirrorssupported by a solar frame formed of a plurality of extruded profilesincluding chords, chord sleeves and strut end pieces. Each chord sleevehaving at least one chord sleeve fin. Each chord sleeve positioned aboutone of the chords. The frame has a plurality of struts. At least onestrut having a strut end piece having at least one strut end piece finthat connects with a chord sleeve fin to connect the plurality ofchords, and a platform supported by the chords and struts on which thesolar mirrors are disposed. There is the step of moving the framerelative to the sun.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

In the accompanying drawings, the preferred embodiment of the inventionand preferred methods of practicing the invention are illustrated inwhich:

FIG. 1 shows a 3D line drawing of the frame of the present invention.

FIG. 2 shows the complete parts list and geometry overview of thepresent invention.

FIG. 3 shows an end view of solar frame of the present invention.

FIG. 4 shows a side view depicting the struts, chords, I-beams and otherparts of the solar frame of the present invention.

FIG. 5 shows a top view depicting all of the struts, chords, I-beams andother parts of the solar frame of the present invention.

FIG. 6 shows a top view depicting the vertical struts (dashed) and topstrut layer between I beams and other parts of the solar frame of thepresent invention.

FIG. 7 shows a top view depicting the vertical struts, I beams and otherparts of the solar frame of the present invention.

FIG. 8 shows the struts and associated linear lengths and information onthe mirrors of the solar frame of the present invention.

FIG. 9 shows a 3D line drawing of the struts, strut end pieces, chordsleeve, chord and I-beams of the solar fame of the present invention.

FIG. 10 shows a 3D line drawing of the struts, strut end pieces, chordsleeve, chord and I-beams of the solar fame of the present invention.

FIG. 11 shows a 3D line drawing of the struts, strut end pieces, chordsleeve and chord that would attach to the I-beams of the solar fame ofthe present invention.

FIG. 12 shows a 3D line drawing of the struts, strut end pieces, chordsleeve and chord at the bottom center of the solar fame of the presentinvention.

FIG. 13 shows a 3D line drawing of a strut, strut end piece, chordsleeve and chord at the bottom right of the solar fame of the presentinvention.

FIG. 14 shows a 3D line drawing of the struts, strut end pieces, chordsleeve and chord at the bottom right of the solar fame of the presentinvention.

FIG. 15 shows the cross sectional profile of strut U of the solar frameof the present invention.

FIG. 16 shows the cross sectional profile of strut M of the solar frameof the present invention.

FIG. 17 shows the cross sectional profile of strut P of the solar frameof the present invention.

FIG. 18 shows the cross sectional profile of strut O of the solar frameof the present invention.

FIG. 19 shows the cross sectional profile of strut W of the solar frameof the present invention.

FIG. 20 shows the cross sectional profile of strut N of the solar frameof the present invention.

FIG. 21 shows the cross sectional profile of strut end piece I7 of thesolar frame of the present invention.

FIG. 22 shows the cross sectional profile of strut end piece I4 of thesolar frame of the present invention.

FIG. 23 shows the cross sectional profile of strut end piece I3 of thesolar frame of the present invention.

FIG. 24 shows the cross sectional profile of strut end piece I1 of thesolar frame of the present invention.

FIG. 25 shows the cross sectional profile of strut end piece I2 of thesolar frame of the present invention.

FIG. 26 shows the cross sectional profile of strut end piece I5 of thesolar frame of the present invention.

FIG. 27 shows the cross sectional profile of strut end piece I6 of thesolar frame of the present invention.

FIG. 28 shows the cross sectional profile of chord C1 a of the solarframe of the present invention.

FIG. 29 shows the cross sectional profile of chord C1 b of the solarframe of the present invention.

FIG. 30 shows the cross sectional profile of chord F of the solar frameof the present invention.

FIG. 31 shows the cross sectional profile of chord sleeve D of the solarframe of the present invention.

FIG. 32 shows the cross sectional profile of chord sleeve E of the solarframe of the present invention.

FIG. 33 shows the cross sectional profile of chord sleeve H of the solarframe of the present invention.

FIG. 34 shows the cross sectional profile of chord sleeve G of the solarframe of the present invention.

FIG. 35 shows the cross sectional profile of Ibeam B1 of the solar frameof the present invention.

FIG. 36 shows the cross sectional profile of Ibeam B2 of the solar frameof the present invention.

FIG. 37 shows the cross sectional profile of Ibeam spacer S1 of thesolar frame of the present invention.

FIG. 38 shows the cross sectional profile of Ibeam spacer S of the solarframe of the present invention.

FIG. 39 shows the assembly drawing of Ibeam B1, strut end piece I7 andspacer S of the solar frame of the present invention.

FIG. 40 shows the assembly drawing of Ibeam B2, strut end piece I1 andspacer S1 of the solar frame of the present invention.

FIG. 41 shows the side view (cut length) of mirror support upright Ja ofthe solar frame of the present invention.

FIG. 42 shows the cross sectional profile of mirror support upright Jaof the solar frame of the present invention.

FIG. 43 shows the mirror upright assembly of parts Ja, Ka and M of thesolar frame of the present invention.

FIG. 44 shows the cross sectional profile of the mirror support rail Kaof the solar frame of the present invention.

FIG. 45 shows the cross sectional profile of the mirror upright assemblybase M of the solar frame of the present invention.

FIG. 46 shows the cross sectional profile of the mirror support rail L1b of the solar frame of the present invention.

FIG. 47 shows the cross sectional profile of the mirror support rail L1m of the solar frame of the present invention.

FIG. 48 shows the cross sectional profile of the mirror support rail Lof the solar frame of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings wherein like reference numerals refer tosimilar or identical parts throughout the several views, and morespecifically to FIGS. 1-48 thereof, there is shown a solar trough frame10 for holding solar mirrors 12 (overview best seen in FIGS. 1, 2 and3). The frame 10 comprises a plurality of chords 14. The frame 10comprises a plurality of extruded profiles, including chord sleeves 16,struts 22 and strut end pieces 18, each chord sleeve 16 having at leastone chord sleeve fin 20, each chord sleeve 16 positioned about one ofthe chords 14. The frame 10 comprises a plurality of struts 22, at leastone of the struts 22 having a strut end piece 18 having at least onestrut end piece fin 24 that connects with a chord sleeve fin 20 toconnect the plurality of chords 14. The frame 10 comprises a platform 26supported by the chords 14 and struts 22 on which the solar mirrors 12are disposed.

At least one chord sleeve 16 and strut end piece 18 may have a circlesize which fits within a 7 inch diameter extrusion press. The strut endpiece fins 24 may interface with the chord sleeve fins 20 so that loadsconverge on a common central point. At least one strut 22 may intersectwith at least one chord 14 in a non-perpendicular fashion. The chordsleeve fin 20 and the strut end piece fin 24 may be thicker at alocation through which the frame 10 fastener extends than at the fin'stip. Each chord sleeve 16 and strut end piece 18 may have a profilecircumscribing circle size less than what would be possible without thestrut end piece 18. Each chord sleeve 16 and strut end piece 18 may bemade of aluminum.

The present invention pertains to a chord sleeve 16 for connecting achord 14 of a solar frame 10 which supports solar mirrors 12 to a strutend piece 18 extending from a strut 22 of the solar frame 10. The chordsleeve 16 comprises a chord sleeve primary portion 30 having an openingin which the chord 14 is disposed; and at least one chord sleeve fin 20extending from the primary portion that is fixed to the strut end piece18.

The chord sleeve 16 may include a chord sleeve fastener 28 which fixesthe chord sleeve primary portion 30 to the chord 14, and a framefastener 32 which fixes the chord sleeve fin 20 to the strut end piece18. The chord sleeve primary portion 30 may be a chord sleeve mainprofile and the chord sleeve fin 20 is a chord sleeve boss extendingfrom the chord sleeve main profile. The chord sleeve main profile andthe chord sleeve boss may be made of aluminum.

The present invention pertains to a strut end piece 18 for connectingthe strut 22 of a solar frame 10 to a chord sleeve 16 which in turnsupport a Platform 26 which support solar mirrors of the solar frame 10.The strut end piece 18 comprises a strut end piece primary portion 34which attaches to the strut 22. The strut end piece 18 comprises atleast one strut end piece fin 24 extending from the strut end pieceprimary portion 34 which attaches to the chord sleeve 16.

The piece may include at least one strut end piece fastener 36 whichfixes the strut end piece primary portion 34 to the strut 22, and aframe fastener 32 which fixes the strut end piece fin 24 to the chordsleeve fin 20.

The strut end piece primary portion 34 may be a strut end piece mainprofile and the strut end piece fin 24 is a strut end piece bossextending from the strut end piece main profile. The strut main profileand the strut boss may be made of aluminum. The strut end piece primaryportion 34 may have an essentially flat side 38 to align with anessentially flat side 38 of the strut 22. The strut fin may have atongue ratio of less than or equal to 3.

The present invention pertains to a method for linking a strut 22 of asolar frame 10 which supports solar mirrors 12 to a chord 14 of thesolar frame 10. The method comprises the steps of positioning a strutend piece fin 24 of a strut end piece 18 of the strut 22 adjacent achord sleeve fin 20 of a chord sleeve 16 about the chord 14. There isthe step of fixing the strut end piece fin 24 and the chord sleeve fin20 together with a frame fastener 32 that contacts the strut end piecefin 24 and the chord sleeve fin 20.

There may be the step of attaching the strut end piece 18 to the strut22. There may be the step of attaching the chord sleeve 16 to the chord14. The step of attaching the strut end piece 18 to the strut 22 mayinclude the step of fixing the strut end piece 18 and the strut 22together with a strut end piece fastener 36 that contacts the strut endpiece 18 and the strut 22. The attaching the chord sleeve 16 to thechord 14 step may include the step of fixing the chord sleeve 16 and thechord 14 together with a chord sleeve fastener 28 that contacts thechord sleeve 16 and the chord 14.

The present invention pertains to a method for supporting solar mirrors12. The method comprises the steps of receiving sunlight on the mirrors12 supported by a solar frame 10 formed of a plurality of extrudedprofiles including chords 14, chord sleeves 16, struts 22 and strut endpieces 18. Each chord sleeve 16 having at least one chord sleeve fin 20.Each chord sleeve 16 positioned about one of the chords 14. The frame 10has a plurality of struts 22. Each strut 22 having a strut end piece 18having at least one strut fin that connects with a chord sleeve fin 20to connect the plurality of chords 14, and a platform 26 supported bythe chords 14 and struts 22 on which the solar mirrors 12 are disposed.There is the step of moving the frame 10 relative to the sun.

Implementing the design features, as detailed below will lead toglobally optimizing frame 10 extrusion, fabrication, transportation, andsite assembly while meeting all technical, structural, and ongoingmaintenance requirements. The frame 10 of the present invention makesefficient use of the extruded metal to optimize the weight andconstruction costs of the frame 10 while exceeding the strength anddeflection requirements; some of the unique connection features allowmore efficient use of material and accurate part connection locations.

The preferred embodiment can best be described as a 12 meter longframework designed to support four rows of parabolic mirrors 12, each ofwhich is comprised of seven mirrors 12 in the row. The design conceptsare applicable to other configurations of length or combination ofmirrors 12; the specific iteration was for the 12 meter frame 10supporting 28 parabolic mirrors 12; the design concepts are alsoapplicable to different geometric arrangements of the chords, chordsleeves, struts, strut end pieces, mirror supports, mirrors and othercomponents. Specific member profiles can vary (simple tubes, D-shapes,etc. . . . ) as design modifications dictate.

Solar trough frames are generally designed so that the outermost framesin the field are strongest, as they are buffeted by winds to a higherdegree while the internal frames are somewhat shielded from thestrongest winds. The design described is for the outermost frames,although the same design philosophies and analyses techniques/iterationswill yield optimal designs for the innermost (lighter) frames as well.

-   -   Referring to FIGS. 1-48, the main components of the structure        are the following:        -   Mirror support structures (Platform) (FIGS. 1-7, 9,10,35-48)            Five different designs—two comprised of capped structural            tubes (FIG. 43) and three as hollow trapezoids with            attachment legs (FIGS. 46-48), with the capped structural            designs spanning higher I-beam to mirror heights and the            trapezoids lower heights; each is designed to minimize            weight while carrying the required structural loads; the            mirror weight and wind loads are transferred efficiently in            an axial manner along the taller tubes.        -   Modified I-beams (FIGS. 1-7,9,10,35-40)        -   One central and two side beams each in seven locations.            Depending on the location and position in the frame 10, the            I-beams may have different dimensions/thicknesses. In            general, the modified I-beams use a wider base and a            narrower top.        -   Chords/Longitudinal Members (FIGS. 1-7, 9-14 and 28-34)        -   One central bottom, two bottom sides, two top sides and two            top centers. These three types of chords differ in design            due to the differing geometries and tensile or compressive            load requirements.        -   To use a basic “D-shape” (FIGS. 9, 12, 13, 14, 28 & 29) with            overall dimensions and wall thicknesses designed to minimize            weight while carrying all required loads as defined by            structural engineering analysis and FEA. The two bottom            sides are the most highly loaded, followed by the two top            sides and then by the one central bottom (depending on            tooling cost, this may be designed the same as the two top            sides, although as a separate design over 2 lbs/frame weight            savings is possible).        -   The two top center chords are also designed to meet the            geometry, structural engineering analysis and FEA            requirements. They look more like “slightly collapsed            trapezoids” (FIGS. 10, 11 and 30) and are designed in this            manner to meet the I-beam angularity requirements.        -   Struts (FIGS. 1-27)        -   Various strut designs (currently six: FIGS. 15-20) as            modified circular/flat extrusions with diameter, wall            thickness and other descriptors dependant on strut length            and both tensile and compressive load requirements.        -   Strut end piece (FIGS. 2, 3, 9-27, 31-40,)        -   Strut end pieces are designed to be fabricated and fastened            to the struts in a factory setting; the strut end piece can            then be connected to the chord sleeves in the field during            frame assembly.        -   Chord Sleeves (FIGS. 1-7, 9-14, 28-40)        -   Four different designs—one for the bottom center, one for            the bottom sides, one for the top sides and one for the top            centers. Each is designed to connect the Chords, I-beams and            struts with the correct geometry and connection means.        -   Fasteners (FIGS. 9-14, 31-40)        -   Various types of fasteners, including “pop rivets”            interference pins, bolts, solid compression rivets or other            types of fasteners to connect the Chords, Chord Sleeves,            Struts, Strut End Pieces, I-beams, and Mirror support            structures.    -   Overview of the structure:        -   End View: (FIGS. 2, 3, 5)        -   When viewed from the end view of the structure, the            parabolic shape of the four rows of mirrors 12 is evident,            as are the three main I-beam supports which the mirrors 12            are connected to via mirror support structure extrusions            fabricated and assembled into the structure required. The            I-beams are in turn supported by a series of struts. From            the end-view the eight struts and the three I-beams make up            a central triangular portion flanked on either side by a            second set of symmetrical triangles which in turn are            flanked on the far right and left by another, different, set            of symmetrical triangles. These triangles could be            asymmetrical (further optimizing the material content of the            frames and performance) if planned installation locations            have a consistent wind direction bias.        -   Side/Top Views: (FIGS. 1, 2, 4-7)        -   When viewed from the side view or from the top, the myriad            interconnections between the various Chords, Chord Sleeves,            Struts, Strut End Pieces and I-Beams is evident. It also            becomes evident that the length of each connecting strut            depends on its 3-dimensional setup—they are generally angled            in all of the end, side and top views. It is also evident            that the design philosophy used was to create triangular            elements in each orientation to ensure that the structure is            stable and strong. Triangles are a very efficient way to            design structures.        -   The angles of the struts to each other and to the I-beams            and Chords leads to the length of the struts; the structural            analysis and FEA work show both the tensile and compressive            forces given various loading conditions (position, wind,            torsion, etc. . . . ); this allows the optimization of each            part's profile design to minimize weight while ensuring that            various loading condition requirements are met, and any            bending, tension or compressive buckling failures are            anticipated and designed around through appropriate            cross-sectional design of the profiles.    -   I-beams In Relation to Mirror Geometry: (FIGS. 1-3, 5, 10)    -   The configuration of the upper I-beams to optimize mirror        support in three planes approximates the shape of the parabolic        mirror, minimizing the required lengths of the mirror support        structures. Four of the eight locations are close enough that        the longitudinal members can be efficiently designed as        trapezoids with attachment legs so that no additional parts,        fabrication or assembly is needed.    -   The two center bottom and two outside top positions have a        position far enough between the mirrors 12 and the I-beams that        an efficient means to bridge this gap is needed (one large cross        sectional profile would weigh too much); using tubular profiles        with a bottom attachment shape to tie the I-beam and tube        together with a “cap” mirror support profile running the length        of the frame 10 on top of the tubes was the most efficient use        of material and fabrication/assembly costs.    -   Geometry:    -   Through structural engineering analysis and FEA, it has been        verified that the struts are subject to axial loads in use with        projected failure modes of compressive buckling normally being        more critical than tensile failure. More nodes were used and        more struts (the “5 triangle end view”) to decrease strut        lengths and thus increase the critical buckling loads, allowing        us to use relatively thin-walled struts designed in cross        section to extrude and fabricate efficiently and to maximize        buckling and tension performance with relatively low weight/ft        (to save on material cost). More nodal connections also allow        the forces to be more uniformly distributed as the mirrors tilt        throughout the day, shifting the weight and the applied wind        loads and torsion.    -   Efficient Assembly:    -   The present method of assembly uses an on-site roller frame to        hold the chords that run the entire length of the truss. Several        people will be sitting in between these members, able to reach        the long members and assemble the frame 10 as it rolls past        them. Each set of rollers could consist of two rollers angled        inward (other configurations are certainly possible and will be        evaluated). This, combined with the weight of the frame 10, will        keep everything securely seated in the apparatus. After each        connection within reach has been attached, the frame 10 will be        rolled to its next stage (the people assembling it will remain        stationary), and the next sets of connections can be made. This        process will be repeated until the entire frame 10 is assembled,        as it rolls out onto some sort of rolling support (for instance,        tires aligned under the 3 bottom long members).    -   With a limited amount of steps per assembler, the assembly will        run smoother and increase quality. It is likely that separate        material handlers will bring the preassembled strut/strut end        piece assemblies, the chord sleeves and the various fasteners to        each of the assembly personnel's locations on site, so that the        assembly personnel do not waste time gathering components. The        entire assembly system is envisioned to be mobile so that as        frames 10 are assembled in the fields in the system, the        completed frames can be lifted off of the exit support rollers        and placed onto the completed uprights already mounted onto the        foundations. In addition, because these frames are typically        located in very hot, arid areas (exceptional sunshine throughout        the year), the “on-site factory assembly system” enables the        operators to be working under an awning with appropriate cooling        fans aimed at them—this will further reduce assembly issues        working in hot conditions; comfortable workers are more        efficient and produce higher quality products.

Struts

-   -   Strut Geometry: (FIGS. 1-27)    -   The present strut design utilizes a thin-walled circular        cross-section (FIGS. 15-20) to maximize the moment of inertia        and radius of gyration while keeping a small area (weight),        maximizing the critical buckling load. Through Finite Element        Analysis iterations showing the expected tensile and compressive        load characteristics we were able to fine tune the profile        geometry/shape to achieve optimal weight to strength ratios and        cross section/diameter/wall thickness optimal for each strut's        unique loading conditions and length.    -   Strut Features:    -   The struts may feature drill guides to facilitate fabrication.        The struts may utilize flat sections to match up to the extruded        and fabricated strut end pieces. Depending on the loading        conditions (tensile and compressive), type of fastener, fastener        diameter and # of fasteners can be adjusted as appropriate.    -   Chords/longitudinal members: (FIGS. 1-7, 9-14, 28-34)    -   There are three types of longitudinal members (chords) which run        the full length of the frame 10 (although these can of course be        assembled from shorter lengths fastened together; most loads on        space frames are axial). Due to the geometry of the solar trough        frame 10 and the expected weight, wind loads and        torsional/rotational loads that the completed assemblies will be        subject to, and the geometries that each must meet, there are        two different designs (discussed above): two various profile        designs of “D's” (FIGS. 28 and 29) and one “collapsed trapezoid”        (FIG. 30). Each is designed to most optimally utilize the        extruded material according to the structural engineering and        FEA analyses, while minimizing the total weight of the solar        trough frame 10 system.    -   Connectors    -   Self-Guiding Chord Sleeve Connectors: (FIGS. 1-7, 9-14, 31-34)    -   These connectors consist of a chord sleeve that may only fit        over the chord member in the correct configuration with at least        one are fin on the chord sleeve used to connect the chords to        the struts or to the I-beams (directly or through strut end        pieces). By using connectors that are pinned (or otherwise        fastened) in place along the chord members, there is a large        reduction in required materials, as the fin(s) that are used to        attach to the struts are only present where they are needed.        These will be fastened to the chords preferably across parallel        walls with chord fasteners and may feature drill guides for        assembly and fabrication ease. The chord sleeves and the strut        end pieces (in fact all fastened parts) are designed with        careful consideration to hole-to-edge distance and wall        thickness to provide the most secure, lightest weight        connection.    -   As noted elsewhere, the self-guiding chord sleeves slide onto        the three “D” designs and the “collapsed trapezoid” in an        efficient manner, and by nature of their smaller circle size        enable the chord sleeves to have a smaller extrusion        circumscribing circle size (hereafter called “circle size”)        which allows them to be extruded on a larger # of available        extrusion presses.    -   The “self-guiding” refers to the ends of the chord sleeve fins        and strut end piece fins including an angled entry point to        facilitate sliding the parts together.    -   Strut End Pieces: (FIGS. 2, 3, 9-27, 31-40)    -   These strut end pieces facilitate easy assembly of the struts to        the chords. These are either pre-drilled/punched or field        fabricated (match drill/punch) and attach to the self-guiding        chord sleeve connectors using fasteners; since they are within        the cross section of the strut OD's (except for the height of        the pop rivet heads), they may in fact best be factory assembled        and shipped as a unit (a “strut assembly” of one strut with two        strut end pieces fastened to it). The strut end pieces may        utilize the flats on the inside of the struts to guide them into        the correct configuration and a small stop may be incorporated        to keep them inserted at the correct depth so no time and effort        is wasted lining up the rivet holes. These extruded and cut to        (short) length strut end piece parts are designed and        drilled/pierced to match with the appropriate struts they will        be inserted into. “Pop rivets” will be used to connect the two        (2 to 6 of various diameters depending on loading expectations).    -   The preferred strut assembly method to fasten the strut end        pieces to the strut, maintaining exceptional tolerances between        the fastener holes on the strut end piece fins on each end of        the strut is as follows:    -   1. Cut strut and strut end pieces to proper length    -   2. Position strut and strut end pieces properly and clamp    -   3. Drill or pierce strut fastener holes    -   4. Place and fasten strut fasteners to join strut end pieces to        strut    -   5. Drill or pierce strut end piece fin holes

This sequence allows the strut assembly to have the same hole tolerancesas a single strut with holes in each end of it.

Please note that all calculations, material properties and safetyfactors were taken from the Aluminum Association Aluminum Design Manual,using the most conservative safety factors used for bridge calculations.For calculation purposes, all extruded materials are assumed to be 6105,6005 or 6005A T6 (although other alloys could be possible). Rivets areassumed to be 2024 T4. All connections are conceived to be riveted withsolid, semi tubular or blind rivets unless otherwise noted, but theassembly can work equally well with pinned, bolted or other fasteningmeans which are also contemplated.

Parts Discussion, Listing and Description

The “Strut End Pieces” are designed to fit inside of the “circular w/flats” struts (although other connection geometries (e.g. outside thestruts) are possible), enabling these to be fastened to the chordsleeves, which in turn fit around and are fastened to the chords. Forpurposes of explanation, the following parts will be discussed (althoughthe same principles apply to all of the other similar parts—just withdifferent dimensions, # fins or slightly different configurations):

-   -   1. Part C1 a (FIG. 28): Bottom Center Chord “D-shape”) that runs        the entire length of the solar frame (Part C1 a is the “lighter”        D used in 3 places (FIGS. 2, 3, 5, 6, 7, 9 and 12), while C1 b        (FIG. 29) is the “heavier” D used in 2 places (FIGS. 2, 3, 5, 6,        7, 13 and 14)    -   2. Part G (FIG. 34): Bottom Center Chord Sleeve that slides over        Part C1 a and is fastened to it (FIGS. 2, 3, 4, 5, 6, 7 and 12)    -   3. Part I2 (FIG. 25): Strut End Piece (with three “fins”) for        Strut M (FIGS. 2, 3, 8, 12, 16 and 25)    -   4. Strut M (FIGS. 2, 8, 12 and 16)    -   5. Part I3 (FIG. 23): Strut End Piece (with two “fins”) for        Strut P (FIGS. 2, 3, 8, 10, 11, 17, and 23)) 14, 19    -   6. Struts P&T (FIGS. 2, 3, 8, 9, 10, 11 and 17))

The Full List of Parts is as Follows:

Struts: Parts M, N, O, P, W & T (FIGS. 1-20) Strut End Piece Connectors:(General: See FIGS. 1-20; specific, see Figures noted below)

Parts I1 (for Strut U's) (FIG. 24)

I2 (for Strut M's) (FIG. 25)

I3 (for Strut P's) (FIG. 23)

I4 (for Strut O's) (FIG. 22)

I5 (for Strut W's) (FIG. 26)

I6 (for Strut N's) (FIG. 27)

I7 (for Strut T's) (FIG. 21)

I-beams: Part B used as Parts B1 (used in 2 places) and B2 (used in 1place) (FIGS. 2-7, 9-11, 32, 35-40)

Part C1 a: Bottom Center and upper left and right Chords (“D-shape”)that run the entire length of the solar frame 10 (FIGS. 2-7, 9, 12 and28)

Part C1 b: Bottom left and right Chord (larger “D-shape”) that run theentire length of the solar frame 10 (FIGS. 2-7, 13, 14 and 29)

Part F: Upper center left and right Chords (trapezoid shaped) that runthe entire length of the solar frame 10 (FIGS. 2-7, 10, 11 and 30)

Part D: Upper left and right chord sleeves that slide over Part C1 a andare fastened to it (FIGS. 2-7, 9 and 31))

Part E: Upper center left and right chord sleeves that slide over Part Fand are fastened to it (FIGS. 2-7, 10, 11 and 32)

Part G: Bottom Center chord Sleeve that slides over Part C1 a and isfastened to it (FIGS. 2-7, 12 and 34)

Part H: Lower left and right chord sleeves that slide over Part C1 b andare fastened to it (FIGS. 2-7, 13, 14 and 33)

Part M: Mirror support structure base (FIGS. 43 and 45)

Part Ja: Mirror support vertical tube (Part M fits into it and isfastened as the “base”) (FIG. 41-43)

Part Ka: Mirror support structure cap that runs the entire 12 meterlength of the frames (FIGS. 43 and 44)

This “caps” Parts Ja and is fastened to each of them to create planesupon which the mirrors 12 can be mounted at the points of greatestdistance from the I-beams

Part L: Mirror rail (2 pieces), Part L1 b: Mirror rail (2 pieces) andPart L1 m: Mirror rail (2 pieces):

These six pieces each run the entire 12 meter length of the frames andare fastened to the I-beams (Parts Q&R) to provide surfaces onto whichthe mirrors 12 can be mounted (FIGS. 46-48)

Myriad of Solid, Semitubular and Blind Rivets, Pins, Bolts, Washers andNuts, Etc. . . .

Overview:

The entire Solar Trough Frame 10 was designed for ease of extrusion,fabrication and assembly with structural engineering calculations andFEA modeling verifying and fine-tuning the concepts and design tooptimize the system in terms of extrudability, part weight andfabrication and assembly ease, while exceeding all structural andfunctional requirements (although extrudability, fabrication andassembly ease also certainly affect the total system cost, the partweight is particularly important). The description below refers to thesix parts detailed above, but the same design concepts andfabrication/assembly/fastening philosophies apply to many other of thechord, chord sleeves, struts and strut end pieces, as well as the othercomponents such as the modified I-beams used in the design.

The structure is designed as a “pinned” assembly, with the struts thussubject to compressive or tensile axial loads. The structuralengineering calculations and FEA verification established the maximumtensile or compressive loads for each component. These maximum loadswere used to specifically design each strut (M, P & T), strut end piece(I2 and I3) and the “fins” on the strut end pieces and bottom chordsleeve (I2, I3 and G). The interior of each strut (M, P & T) may have aflat section of a certain width designed to mate with an associated flatsection width of each strut end piece (I2 and I3).

The Solar Trough Frame 10 design shown uses seven extruded profiles thatrun the entire 12 meter length of the frame 10 (Parts C1 a (used inthree places), C1 b (used in two places) and F (used in two places)).These chords are each surrounded by chord sleeves (parts D (used in 2places), E (used in two places), G (used in 1 place) and H (used in twoplaces). Struts with strut end pieces connect these seven assemblies invarious specifically designed angled planes to create a 3 dimensionaltruss structure. When looking at the frame 10 from the end view thereare 5 triangles. There is a central triangle composed of struts with the“base” of the triangle facing upwards (Triangle 1) attached to thehorizontal I-beam (Part R), two triangles flanking Triangle 1 on eitherside with their “bases” facing down (Triangles 2 left and 2 right) andthen two more triangles (Triangle 3 left and Triangle 3 right), flankingTriangle 2 left on the left and Triangle 2 right on the right with theirmore severely angled “base” facing up and attached to the slantedI-beams (Parts Q).

Triangle 1 is comprised of three corners: the bottom is chord sleevePart G and the upper left and right are chord sleeves Part E. Triangle 2left is comprised of three corners: the bottom most being chord sleevePart G and the left bottom chord sleeve Part H, with the top chordsleeve Part E.

Triangle 2 right is comprised of three corners: the bottom most beingchord sleeve Part G and the right bottom chord sleeve Part H, with thetop chord sleeve Part E.

Triangle 3 left is comprised of three corners: the bottom most beingchord sleeve Part H and the top right chord sleeve E, with the top leftchord sleeve D.

Triangle 3 right is comprised of three corners: the bottom most beingchord sleeve Part H and the top left chord sleeve E, with the top rightchord sleeve D.

While when looking at an end view the assembly gives the impression ofthese 5 triangles all in the same plane, a review of the side view willshow that the various struts actually are also placed at angles notcoplanar with the end view.

-   -   1. Description        -   a. Part C1 a: Bottom Center Chord (“lighter” “D-shape”) that            runs the entire length of the solar frame            -   i. The shape configuration and wall thickness of this                part were designed to provide the necessary ability to                handle the tensile, compressive and bending loads placed                onto it. This piece has multiple lengths of Part G                (Bottom Center Chord Sleeve) slid over it and fastened.                Besides providing the tensile, compressive and bending                strength, Part C1 a's “D” shape enables Part G to be                slid over it and oriented reliably such that the various                fins on all mating parts align properly.        -   b. Strut M (12 pieces)            -   i. The FEA verified maximum tensile force is 2,160 lbs                and compressive force is 2,520 lbs.            -   ii. The strut cross section was designed to ensure that                the tensile and compressive forces possible under the                most severe loading conditions are handled with more                than the conservative bridge safety factors. The strut                length and strut end pieces allow an “effective strut                length” to be calculated. The section's effective                length, cross sectional area, and radius of gyration are                used to calculate allowable compressive and tensile                forces before failure (including buckling, which was the                normal predicted failure mode of most of the strut                assemblies, given their slenderness ratio).            -   iii. The tensile and compressive stresses predicted led                to the calculation of the number of blind 5/16″ aluminum                rivets that would be required to properly secure the                strut end pieces to the strut (other fastener types,                number of fasteners and size can be used as long as they                can carry the necessary shear stresses and the bearing                loads are acceptable).        -   c. When a simple Part G “fin” to Part I2 or I3 “fin”            connection was contemplated, the fastener diameter was            rather large to handle the predicted loads with the needed            safety factor. While the design would allow many types of            fasteners (pins, bolts, or rivets (solid, semitubular or            blind)), we designed it capable of being assembled with            rivets capable of setting via hand squeezers (C or Alligator            jaws). To accomplish the needed maximum of the tensile and            compressive capacity with safety factor, while still using a            rivet diameter capable of being hand squeezed, we needed to            create multiple shear points on the rivets via interlocking            “fins” on Part G and the mating strut end pieces, Parts I2            and I3. The cut lengths of the individual strut end pieces            were calculated, and the flat “ID” of their associated            struts designed to ensure that they both “fit” and could            carry the necessary loads and stresses, given the “fin” or            “tab” widths, thicknesses and fastener hole diameters.

Part G: Bottom Center Chord Sleeve that Slides Over Part C1 a and isFastened to it (Likely Pinned, Riveted or Bolted).

-   -   i. This part is configured to allow multiple struts at various        compound angles to be fastened to it (Struts M, P & T via their        respective Strut End Pieces (I2, I3 and I4), respectively) and        also to allow Strut N and other Strut End Piece I6 to connect to        Part G. Looking at an end view of the assembly and the        extrusions shows how the angles for each of the struts in one        dimension are defined. The “fins” on Part G interface with the        “fins” on the Strut End Pieces. The faces of each allow close        connections to minimize fastener bending and allow Parts I2 and        I3 to be positioned both along the length of Part G and at the        appropriate angle (looking at a side view of the assembly) as        required. Each connection is designed to be secured with a        fastener, such as a bolt, pin or rivet (blind, solid, semi        tubular or other).    -   ii. The fin designs are such as with other cases throughout the        frame 10 design, that the loads converge on an essentially        common central point to avoid creating complex moments in Part G        (this design philosophy is used with the other components in the        structure as well).    -   iii. Part G is designed to keep a relatively small circle size        (5.94 inches, extrudable on the most common 7″ extrusion press        diameter) to allow this part to be extruded on a variety of        extrusion presses commonly available (where possible, we        maintained lower circle sizes than other designs to allow        flexibility in choosing which suppliers and which of their        extrusion operations could actually extrude the parts).    -   iv. Each of the fins on Part G is specifically designed to both        provide the mating portion to correctly interface with the strut        end piece fins 24 and to ensure that they are both strong enough        in tensile and compressive capacity and bearing and extrudable        at the same time. FEA analysis was used to precisely determine        the tensile and compressive loads on each strut and thus on each        of their connectors as well. “Pinned” fasteners were used for        the FEA, which can be accomplished via pins, rivets, bolts or        other means. For sizing purposes, the maximum tensile and        compressive loads were used to size rivets with single or        multiple “shear points” in a way such that smaller diameter        rivets could be used where needed, while still providing the        necessary load capacity. Single fins on the chord sleeves can be        used, but in this specific example, sizing the parts and        geometries to allow the use of hand set rivets, for example,        multiple “fins” on Part G and the various strut end pieces        (Parts I2 and I3) allowed for the hole diameters to be        minimized, keeping the circle size of all of the parts within        readily available commercial extrusion operation limits.        -   d. The specific design of the fins ensures that they can            carry the necessary loads, provide appropriate bearing            strength for the fasteners and mating parts, provide mating            surfaces for the strut end pieces (Parts I2 and I3) and to            ensure that they are of such a configuration that the            “extrusion tongue ratio” is acceptable from an extrusion and            extrusion tooling perspective. The “extrusion tongue ratio”            is critical, as for parts such as G with a long void between            the fins, the ratio is defined as the area of the die            tongue/(the base width of the tongue^2). The design we            developed ensures that Part G and the mating strut end            pieced parts I2 and I3 can be rotated around the fastener to            create the appropriate truss angles, while not having the            straight cut ends for the parts, each of which are cut to a            particular length, interfere with the mating part upon            rotation. The “end-to-hole” design is such to guarantee that            the fins can support the needed compressive and tensile            loads transmitted through the fasteners, and yet create the            largest “base” of the tongue to maintain the tongue ratios            below industry preferred 3:1.        -   e. Part I2: Strut End Piece (with three “fins”) for Strut M            -   i. As described above, this part cross section was                designed to carry the needed loads and with the three                “fins” to create four shear points on the fastener which                connects it to Part G.            -   ii. Using 5/16″ diameter blind aluminum rivets, four                rivets are required to carry the FEA predicted loads.            -   iii. There may be an “end stop” designed into each of                the strut end pieces to provide a positive “stop”                against which the cut strut extrusions bear to ensure                accurate strut to strut end piece orientation and                location.        -   f. Part I3: Strut End Piece (with two “fins”) for Struts P            -   i. Same discussion as for Part I2, but the lower load                requirements of Struts P led to only three fastener                shear points required holding these to Parts G, and thus                they only have 2-vs-3 “fins”        -   g. Struts P&T            -   i. Similar discussion to Strut M, but smaller                loads=smaller cross sections, etc.

While the term “riveted” is used, other fastening methods arecontemplated and may be used in the solar trough frame 10 construction.

Struts transfer loads axially.

All chord sleeves (D, E, G and H) are fastened to their respective chordmembers (C1 a, F, C1 a and C1 b respectively) via blind rivets to keepthe chord sleeve located axially along the main chord members.

Mirror→Mirror Supports (Ka, L1 b, L1 m and L)→1-Beams (Parts B1 and B2)

The parabolic mirrors 12 are attached to the frame 10 via support boltsextending from the back of the parabolic mirrors 12, connected to themirrors 12 by a ceramic pad (this is a commercially available mirrorsystem from Flabeg (RP3), although the frame designs could easily bemodified to handle other mirror systems). These connect the mirrors 12to parts Ka, L1 b, L1 m and L; the bolts are part of the mirror 12 andare inserted through holes in these parts, secured with nuts and washersfrom the underside of the parts. These bolts attach the mirrors 12 toparts Ka, L1 b, L1 m and L to support the mirrors 12 whateverorientation the frame 10 is (the frame 10 rotates to follow the sun).The entire solar trough is designed to handle the worst case conditionsof the weight of the mirrors 12, the frame 10 itself and the wind loads(and associated twisting loads (described later) which the positioningand wind conditions place on the system.

Parts L1 b, L1 m and L are in turn directly riveted to the I-beams. PartKa is placed over and riveted to Part Ja, and Ja is placed over andriveted to Part M (see drawings); Part M is then riveted to the I-beam.

The loads transfer from the mirror bolts to Parts Ka, L1 b, L1 m and Land then to I-beams B1 and B2 (either through Parts L1 b, L2 m and L orthrough Ka to Ja to M).

Strut End Pieces (I1, I2, I3, I4, I5, I6 and I7)→Struts (Struts M, U, T,P, W, N and O)

Each strut has an associated Strut End Piece which fits inside it and isblind riveted (or otherwise pinned or fastened) to the flat portions (ifflats are used) of the ID of the struts.

Strut End Pieces to Chord sleeves (Parts G, H, D & E)

I-Beams (Parts B1 and B2) (+Spacers: Parts S and S1)→Strut End Pieces(Parts I1 and I7)

Spacers S1 sits directly under the bottom flanges of the I-beam B2(which is used at the “base” of the parabola). It is fastened (likelybolted due to the forces involved and resulting required fastenerdiameter) and used to provide additional tensile and compressivestrength to the strut end piece (Part I1) to I-beam flange connectionand to create a large enough gap on the strut end piece (Part I1) toallow the strut end piece to have sufficient tongue support forextrusion purposes. Modifications to the I-beam profile may allow thedesign to be accomplished without these spacers. Strut U is attached toStrut End Piece Part I1 via blind rivets or other fasteners. Part I1surrounds and is fastened to the “sandwich” of the bottom flange ofI-beam B2 and Spacer S1.

Spacers S sits directly under the bottom flanges of the I-beam B1 (whichis used in two places as the left and right “legs” of the parabola). Itis fastened (likely bolted due to the forces involved and resultingrequired fastener diameter) and used to provide additional tensile andcompressive strength to the strut end piece (Part I7) to I-beam flangeconnection and to create a large enough gap on the strut end piece (PartI7) to allow the strut end piece to have sufficient tongue support forextrusion purposes. Strut T is attached to Strut End Piece Part I7 viablind rivets (or other fasteners). Part I7 surrounds and is fastened tothe “sandwich” of the bottom flange of I-beam B1 and Spacer S.

Struts T and U are used to keep the I-beams B1 and B2 parallel,counteracting any forces from weight or wind.

Part E (Chord Sleeve)→I-Beams (B1 and B2), Part G (Chord Sleeve)/Part C1a (Chord Member), Part H (Chord Sleeve)/Part C1 b (Chord Member), Part D(Chord Sleeve)/Part C1 a (Chord Member)

The angled legs of Part E (along the 4.926″ dimension) are fastened tothe bottom flanges of I-beams B1 and B2 (likely bolted due to loadrequirements and resulting fastener diameters). Any loads from themating portions of I-beams B1 and B2 are transferred through Part E(chord sleeve) to Part F (chord member) and through strut end pieces 13and 14 to Struts P and O. Strut P then transfers axial loads to Part Gat the base of the solar frame (and then to chord member C1 a and StrutsN and M through strut end pieces I6 and I2 respectively). Strut O thentransfers loads to strut end piece I4, then to chord sleeve H and tochord member C1 b; Chord sleeve H supports loads from Strut W throughstrut end piece I5 and Strut N and M through strut end pieces I6 and I2respectively).

The upper left and right “legs” of the parabola I-beams B1 are connectedto chord sleeve D. Part C1 a (identical extrusion to that used in Part Gchord sleeve) goes through the center of Part D. The angled fins onchord sleeve D connect to the fins on strut end piece I5 which in turnis attached inside of Strut W.

The weight and wind loads are transferred through this assembly.

Frame 10 Mounts→Mounting Towers

All of the forces of the frame 10 and mirror 12 weights and wind loadsare eventually supported by frame 10 mounts at each end of the solartrough frame 10. At the ends of the 12 meter solar trough frame 10 thereare assemblies which support the ends of the solar trough frame 10 andtransfer the loads to a rotating (customer supplied) mechanism on top ofcustomer supplied towers mounted on concrete foundations. They aretriangular assemblies of I-beams (conceived as 2.5″ top flange, 4.0″bottom flange (each with 0.187″ walls) and a total height of 3″),although specific customer requirements will likely change the form ofthese end supports.

How the motor will rotate the mirrors 12:

The solar frames are arranged end to end with a motive force applied,for example, between frames 4 and 5 (of an 8 frame line for thisexample). Frame 1 is linked to 2, 2 to 3 and 3 to 4, and frame 8 to 7, 7to 6, and 6 to 5. Between frames 4 and 5 there will be an electric orhydraulic motor mounted on a stand and powering a gearbox with a twosided power takeoff shaft in line with the rotational axis of the solarframes—each side of the power takeoff is attached to frames 4 and 5respectively. The motor drives the gearbox which in turn rotates frames4 and 5 at the same time. Frames 3-2-1 and 6-7-8 rotate in concert dueto their attachment to frames 4 and 5 respectively. The motor/gearboxestablish the rotational orientation of the line of frames, holding themin position against weight and wind loads, and rotating them to followthe traverse of the sun across the sky.

Description of Part D:

Part D is the chord sleeve which surrounds Part C1 a (a “D” shape,coincidentally, which is a chord member running the full 12 meter lengthof the frame). Part D is fastened to part C1 a to position it along thelength of C1 a. Part D is also fastened to I-beam part B1 and to thestrut end connectors for Strut W, Parts I5. The “D” shape of Part Dencompasses Part C1 a providing resistance to rotation of chord sleeve Daround the chord member C1 a. The flat projections above and below theleft edge of the “D” (viewed as the letter, not as used in the assembly)are pierced with holes to allow fastening to I-beam part B1. Theconnection point for Parts I5 are shaped with a larger bulge in thecenter to allow the corresponding “tongue” portion of I5 to have a wideenough “base” such that the [tongue area of I5/“base”^2] is 3 or less(the preferred “tongue ratio”-easier to extrude without the extrusiondie “tongue” having excess deflection and breakage). The “end” of thisconnection point narrows down to the wall thickness required to carrythe projected FEA tensile and compressive loads, with a length longenough that the hole to edge distance of the hole in the wide part ofthe “bulge” is at least 1.0× the diameter (actually, it is slightlygreater than 1.0× the diameter). By narrowing the bulge back down tothis required wall thickness, the area of the corresponding “tongue” ofpart I5 is kept as small as possible to keep the tongue ratio lower than3.0.

How the Solar Frames are Mounted and Rotated

The concentrated solar thermal power plants are made up of thousands offrames. They are arranged in multiple parallel rows of mirrors 12, eachrow of which rotates to follow the progress of the sun across the sky tooptimize solar reflection onto the receiver tube. The mirrors 12 are“linked” together in a row (FIG. 1) and a number of mirrors 12 arerotated at once, using electric or hydraulic motors with gear boxes.

Each individual mirror frame is supported by two deep concrete padspoured into the earth (with steel rebar) at each end of the mirrorframe; these foundations are supplied by others. On top of each concretepad are truss-like “uprights” (supplied by others). Each solarframe/mirror assembly is equipped with structural assemblies on eachend; these are manufactured from structural extruded parts fabricatedand assembled/fastened into structures which are then fastened to eachend of the frame. The top of these structures will be located at thecenter of gravity of the frame/mirror combination (with the currentdesign, this is just above the top surface of the mirror at the bottomof the parabola). Bearing devices (supplied by others) will be attachedto the truss-like uprights and will attach to the structures at each endof the frame so that the frames can easily be rotated about their centerof gravity, despite the total weight of the frames and mirrors 12.

Between each two frames are connecting mechanisms (supplied by others)that “tie” the two frames together so that they rotate around the sameaxis at the same time. If, for example, there are 18 frames in each rowof mirrors 12, there will be a drive mechanism in the center, connectedto frames 9 and 10 directly powering them. Frames 1-9 and 11-18 are thenrotated because they are “tied” together between each frame. Therotation allows the mirror 12 to follow the sun across the sky. Due towind conditions in the locations where these mirrors 12 are installed,the wind will want to rotate the mirrors 12. The connections betweeneach two mirrors 12 linking back to the gear drive electric or hydraulicmotor resists this force.

Although the invention has been described in detail in the foregoingembodiments for the purpose of illustration, it is to be understood thatsuch detail is solely for that purpose and that variations can be madetherein by those skilled in the art without departing from the spiritand scope of the invention except as it may be described by thefollowing claims.

The invention claimed is:
 1. A frame for holding objects comprising: aplurality of chords; a plurality of extruded profiles, including chordsleeves and strut end pieces having strut end piece fins, the strut endpiece fins have an extrusion tongue ratio of less than 3:1, each chordsleeve having at least one chord sleeve fin, each chord sleevepositioned about one of the chords; a plurality of struts, at least oneof the struts supporting a compression force of 2520 lbs. and attachedto one strut end piece having at least one strut end piece fin thatconnects with a chord sleeve fin to connect the plurality of chords, thestrut end piece separate and distinct from the strut; and a platformsupported by the chords and struts on which the objects are disposed, atleast one chord sleeve with the chord sleeve fin and strut end piecehaving a circle size which fits within a 7 inch diameter extrusionpress.
 2. The frame as described in claim 1 wherein the strut end piecefins interface with the chord sleeve fins so that loads converge on asubstantially common central point.
 3. The frame as described in claim 2wherein at least one strut intersects with at least one chord in anon-perpendicular fashion.
 4. The frame as described in claim 3 whereinthe chord sleeve fin and the strut end piece fin is thicker at alocation through which a frame fastener extends than at the fin's tip.5. The frame as described in claim 4 wherein each chord sleeve and strutend piece are made of aluminum.
 6. The frame as described in claim 5wherein at least one chord sleeve comprises: a chord sleeve primaryportion having an opening in which the chord is disposed; and at leastone said chord sleeve fin extending from the primary portion that isfixed to the strut end piece fin.
 7. The frame as described in claim 6including a chord sleeve fastener which fixes the chord sleeve primaryportion to the chord, and a frame fastener which fixes the chord sleevefin to the strut end piece fin.
 8. The frame as described in claim 7wherein the chord sleeve primary portion is a chord sleeve main profileand the chord sleeve fin is a chord sleeve boss extending from the chordsleeve main profile.
 9. The frame as described in claim 8 wherein atleast one strut end piece comprises: a strut end piece primary portionwhich attaches to the strut; and at least one said strut end piece finextending from the strut end piece primary portion which attaches to thechord sleeve.
 10. The frame as described in claim 9 including at leastone strut end piece fastener which fixes the strut end piece primaryportion to the strut, and a frame fastener which fixes the strut endpiece fin to the chord sleeve fin.
 11. The frame as described in claim10 wherein the strut end piece primary portion is a strut end piece mainprofile and the strut end piece fin is a strut end piece boss extendingfrom the strut end piece main profile.
 12. The frame as described inclaim 11 wherein the strut primary portion has a substantially flat sideto align with a substantially flat side of the strut.